Manufacture of cellulose



Patented a. 6, 1925,

UNITED STA moms nnen'our 15s vams, or manna, amen muraeruna or cntnunosn i no Drawing.

. To all whom it may concern: I

Be it known that I, ANTOINE RneNour on VAINS, a citizen of the Republic of France, residing at 10 Rue Henri Grosbon; Miribel,

6 Ain, France, have invented new and useful Improvements in the Manufacture of Cellulose, ofwhich the followingis a specification. T The present invention relates to a process .10 for neutralizing the acids set free by the chlorination of cellulosic material treated with chlorine with a view to bleaching and for dissolving the chlorinated products, such as ketonic chlorides, resultin from this treatment. The inventor has already proposed a process of this kind which consists in treating the chlorinated cellulosic material (paper'- pulp) with bases of the alkali earth metals or with salts of the alkali earth metals whose acid is weaker than hydrochloric acid. This process is. subject to the drawback that it introduces into the paper-pulp 5 after chlorination a considerable quantity of It has been found impossible in practice to obtain an exact, neutralization of the prodnets to be destroyed and, it is necessary to use an excess of bases or salts of thealkali earth metals, which excess remains in the pulp and prevents it being properly bleached. This process isdescribed in grQench Patent No. 550,925, granted May 3,

On the other hand, the inventorhas also 1 proposed another process (U. S. Patent No. 1,455,495, granted February 13, 1923), which provides-for the solution of the chlorinated derivatives, resulting from the treatment of li'gnoand pecto-cell'ulose by chlorine, byv means of soda residuary liquors, which have already served to lixiviate cellulosic material. This process is subject to the serious drawback that it consumes a considerable. quantity of these liquors and, owing to this circumstance, the "soda element whichthey contain-is entirely lost. The present invention enables these drawbacks to be overcomeiin a satisfactory manner and it consists in combining the two brown-processes, thatis to say: in treating the, chlorinated lignoand 'pecto-cellulose can a restricted quantity ofbases' or salts bases or salts of the alkali earth -metals."

a pumion filed 0mm 1a, 1923. Serial no. ceases.

' of the alkali earth metals so as to obtain an approximate neutralization of the acids set free by the chlorination; in washing thepulp which has been neutralized in this mannenand in treating it with the residuary soda liquors or any other sodium hydroxide solution, such as a solution of sodium hy-.

droxide', of sodium carbonate, sodium sulfphite and the like, with a view to rendering soluble thederivatives' formed during the chlorination, which derivatives can then easily be eliminated by washing'with water; the chlorinated products are thus eliminated after a preliminary stage or neutralizing stage, by treating the pulp with bases or salts of the alkali earth metals and the sec- 0nd stage or stage of solution of the chlorinated products, is efiected withthe help of soda reagents. The technical eflect of .the present invention results from the statements given above, and the economic effect consists in the fact that a great saving 'in soda reagents is eflectedas compared with the known process? said reagentsbeing replaced by reagents of the group of alkali earth metals'which are less'expensive and which, however, perform the same work. Furthermore, the cellulosic material obtained does not contain an excess of alkali earth metals which are prejudicial to the whiteness ofthe pulp. v

' When carrying out the invention 1n practice, the chlorinated pulp is fed continuously to a malaxating' apparatus of anysuitable I form, having either a vertlcal shaft, a hor1-' zontal shaft or being provided wi th baflies. At the same -time,'there is contlnuously fed to the same-.malaxatingapparatus, either a milk of lime'or a milk of calcium carbonate,

order to extract the alkali earth metal chloor salt of any other alkali earth-metal. The

rides formed wlich, if these precautions were not taken, would react with. the soda in the subsequent alkaline treatment and would consequently is then treated with an alkaline base such 'as caustic soda, with a salt of anacid weaker than h as sodium carbonate,s i'um sulphite and the like. The solution of the chlorinated one of these bases formed by consume alarge 'quan- 'tity of valuable reagent. The pulp obtained drochloric acid, such ivacaustic potash or ammonia or,".-

tives is then very economically effected by.

lixiviation with water and the pulp is then finally bleached b the usual process.

Any residuary iquors, whether of soda or alkali earth metals, having already served for the lixiviation of cellulose material in other operations, may be used as reagents.

I claim:

1. Process for neutralizing the acids set free by the chlorination of cellulosic material and for dissolving out the chlorinated derivatives, consisting in neutralizing, b means of a compound of the alkaline eart metals, the chlorinated cellulose and in rendering soluble, by means of an alkaline compound,the chlorinated derivatives formed durin chlorination.

2. process, as in claim 1, in which the cellulosic ulp is washed after the operation of neutralization.

3. A' process as in claim 1, in which the chlorinated derivatives are washed out after theyhave been rendered soluble.

4. .A'processas in claim 1, in which the chlorinated derivatives are washed out after they have been rendered soluble and the pulp has been neutralized.

5-. A process as in claim 1, in which the compound of an alkaline earth metal consists of a residuary liquor of the alkali earth metal group, which has already served for lixiviating cellulosic material during other operations.

6. A process as in claim 1, in which the alkaline compound consists of an alkaline residuary liquor having already served for lixiviating cellulosic material during other operations.

ANTOINE REGNOUF DE VAINS. 

